I. Field of the Invention
The present invention relates generally to the field of labeling and, in particular, the present invention provides a continuous in-line process for constructing multi-ply resealable labels that accommodates intermediate plies smaller in size than the overall label dimensions.
II. Related Art
Multi-ply labels, variously referred to as xe2x80x9cmulti-layeredxe2x80x9d, xe2x80x9cextended textxe2x80x9d, xe2x80x9cexpanded contentxe2x80x9d or xe2x80x9cbookletxe2x80x9d labels, carry text on a plurality of surfaces and are useful for consumer products, particularly those sold in bottles, cans, cartons, and tubes, where it is desirable to present additional information to the consumer which cannot conveniently be contained on a single printed label surface. Particularly in view of the increasing amount of governmental regulation and labeling requirements, many consumer products contained in such packaging must carry additional information including detailed instructions for use, detailed listings of the contents, a variety of consumer product warnings, and provisions for multi-lingual information.
Multi-ply labels normally contain two or more layers or plies of label material hinged together adhesively along one margin, and close utilizing a pressure sensitive release-reseal system along the opposite margin. It is often desirable that one or more internal, middle or intermediate plies be added between an upper or top ply and a bottom or base ply. It is further advantageous if the intermediate plies can be hinged between the top ply and base plies yet not interfere with or be required to be part of a release-reseal closure system involving top and base plies. This can be accomplished by making internal or intermediate plies shorter than the top and base plies so that the free ends of the intermediate plies do not extend into the release-reseal margin area. In this way, intermediate plies are hinged like the pages of a book when a label is open, yet are confined within a resealed or closed label.
While the above is a desirable configuration or label construction for labels of a class having three or more plies, automation of an in-line, single pass process to mass produce such labels has been thwarted. One problem arises because the slightly smaller intermediate ply or plies must be sized separately and prior to any final sizing cut for the assembled labels. This problem, among others, has heretofore proved to be an impediment to mass production in-line, single pass automation.
One in-line process for multi-ply labels is illustrated and described in U.S. Patent Application Publication US 2002/0084026 A1 to Matthews et al., teaching the use of a pressure-sensitive adhesive overlaminate to hold two webs together. That in-line construction, however, results in a costly and unnecessarily complex multiple layer label.
Thus, it would present a distinct advantage if the process for making hinged multi-ply labels could be simplified and automated, particularly for those multi-ply labels designed to have one or more under-sized intermediate plies configured in resealable booklet-label form.
In accordance with the present invention, there is provided a process for manufacturing resealable multi-ply labels that includes a first or base ply having an under side and an upper side and typically an amount of a pressure sensitive adhesive (PSA) material (defined below) on the under side to attach the label to an object, normally a container of interest to be labeled. A top ply is provided having-an upper side and an under side and the upper side of the base ply and the under side of the top ply are designed to be joined together permanently along a first or hinge edge or hinge strip, preferably by an amount of a permanent adhesive (PA) material (defined below), which is not pressure sensitive and which thereby forms a permanent hinge. Of course, in some applications, hinges may be conveniently formed using a pressure sensitive adhesive material (PSA) (also defined below).
As will become apparent, an important aspect of the process of the invention involves in-line, single pass inclusion of additional middle or intermediate plies which are attached between the top ply and the base ply. Intermediate plies may be attached using (i) a portion of the hinge strip fastening the base ply to the top ply, or (ii) using multiple hinges, one provided between each of the layers or plies in sandwich fashion.
The upper side of the base ply and the under side of the top ply are also releasably, resealably, joined along an opposite or second edge or along an outer release-reseal margin opposite the hinge or at one or more release-reseal strips spaced from a central hinge strip (depending on the label configuration). A dual layer release-reseal system is used which includes a layer of pressure sensitive adhesive material and an abutting layer (top/bottom) of a release coating such that the plies can be separated and resealed at a juncture therebetween.
The present invention relates to the in-line, single pass manufacture of such labels, particularly those having middle or intermediate plies. More particularly, the present invention relates to such manufacturing of labels having one or more intermediate plies that are of a size different from that of the base and top plies or the overall label size. Most notably, the present invention accomplishes simplified in-line, single pass manufacture of multi-ply labels in which one or more undersized (shorter) intermediate plies are included within a booklet label. The labels are preferably processed continuously using multi-unit (modular) in-line narrow or wide web printing and converting platform presses selectively capable of providing a variable number of printing and converting stations. This includes stations for the application and drying of pigmented inks, coatings and adhesives of different types and stations accomplishing converting processes such as unwinding, turning, die cutting, joining and re-winding.
The manufacturing process may be carried out by using multiple continuous webs, i.e., one web per ply, using a single continuous web, or some combination thereof. In any event, the process enables the continuous production of multi-ply labels having intermediate or middle plies of smaller size, particularly shorter than those of the top and base plies. This is accomplished in one preferred embodiment by providing a web die cutting step prior to a web joining or ply assembly step in the case of a multi-web system, in which, more importantly, the die cutting step is one that does not disturb web integrity. In another preferred process embodiment, a xe2x80x9cwindowxe2x80x9d-creating die cutting step is provided in a single web label generating system which removes a portion or xe2x80x9cwindowxe2x80x9d of unwanted material from intermediate plies to accomplish size reduction.